Phenotype of normal spirometry in an aging population.

Area of Science:

• Pulmonology
• Respiratory Medicine
• Diagnostic Criteria

Background:

• The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines may misclassify normal spirometry in aging populations, leading to inaccurate diagnoses of respiratory impairment, including chronic obstructive pulmonary disease (COPD).
• Accurate spirometry interpretation is crucial for managing respiratory conditions and avoiding unnecessary interventions.

Purpose of the Study:

• To evaluate the phenotype of normal spirometry using the Global Lung Initiative (GLI) criteria.
• To compare GLI-defined normal spirometry with GOLD spirometric categories and assess phenotypic characteristics.

Main Methods:

• Analysis of spirometry and multiple phenotypes in 10,131 participants (ages 45-81) from the COPDGene study.
• Phenotypes assessed included dyspnea, quality of life, 6-minute-walk distance, bronchodilator reversibility, emphysema, gas trapping, and small airway dimensions.

Main Results:

• Among 5,100 participants with GLI-defined normal spirometry, GOLD misclassified 22.5% as having respiratory impairment.
• Phenotypic characteristics for GLI-defined normal spirometry were within normal ranges across various measures, including dyspnea, quality of life, and lung imaging.
• These normal phenotypes persisted even when GLI-defined normal spirometry was categorized under GOLD guidelines.

Conclusions:

• GLI-defined normal spirometry demonstrates normal phenotypic characteristics, even when GOLD criteria suggest respiratory impairment.
• The findings suggest that GOLD guidelines may misclassify normal lung function as respiratory impairment in adults.
• Utilizing GLI criteria may lead to more accurate spirometry interpretation and patient management.